Seeing with his prophetic eye that the seed of Jacob would once be compelled to go into exile, Isaac offered up one more petition, that God would bring the exiles back again. He said, "He shall deliver thee in six troubles, and in the seventh there shall no evil touch thee." And also Rebekah prayed to God in behalf of Jacob: "O Lord of the world, let not the purpose prosper which Esau harbors against Jacob. Put a bridle upon him, that he accomplish not all he wills to do."
When Esau observed that even his father's love had passed from him to Jacob, he went away, to Ishmael, and he addressed him as follows: "Lo, as thy father gave all his possessions to thy brother Isaac, and dismissed thee with empty hands, so my father purposeth to do to me. Make thyself ready then, go forth and slay thy brother, and I will slay mine, and then we two shall divide the whole world between us." And Ishmael replied: "Why dost thou want me to slay thy father? thou canst do it thyself." Esau said: "It hath happened aforetime that a man killed his brother- Cain murdered Abel. But that a son should kill his father is unheard of."